Re: Aquatic Plants Digest V3 #805

[Christopher Ferrell <csferrel at eos_ncsu.edu>]

Has anyone thought about finding one of these that has a light or makes a buzzing
sound when a certain temperature is reached and then using that output to flip a
relay to control undergravel heating cables?  When the light or the speaker comes on
it is activated by a certain voltage, run this through a transistor then to the
relay and then have the relay turn the 120v side of the transformer on and off.
Anyone tried it?  Just my engineering based musing.

Chris


Date: Tue, 26 Jan 1999 07:12:40 -0800 (PST)
>From: Erik Olson <erik at thekrib_com>
Subject: Re: The latest gadget

On Mon, 25 Jan 1999, George Booth wrote:

[Thermometers]
> Recently, I found another model that is digital (HOO-HAH!) It reads
> from - -58 to 302 degrees F. The resolution is 0.1 degree F! Simply
> awesome for $19.

I think Hanna Instruments carries something very similar to this -- we
bought it for around that price.  I wonder if the resolution is that good
though.  It's called the "Checktemp II", and we got it off the Hanna site
(wwww.hannainst.com I think).

Pretty silly when you consider that the Radio Shack +/- 2 F thermometers
are selling for similar prices.  No contest!

  - Erik

- --
Erik Olson
erik at thekrib dot com

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